Anthropic Says Claude Traced NIST ECDSA Curve Seeds to a 1990S RNG

Anthropic’s Frontier Red Team reported in a research publication on October 16, 2026, that an internal Claude research model had traced the origins of the NIST ECDSA curve seeds to the C library’s lrand48 random-number generator seeded with Unix timestamps, answering a provenance question that had been open since the NSA supplied the values without explanation.

ECDSA is the most widely used elliptic curve cryptography standard. NIST adopted it in 2000 as part of the FIPS 186-2 Digital Signature Standard, which lists standard elliptic curves of varying sizes and security levels. For curves over prime and binary fields, the specification published a seed parameter whose hash value defines the coefficient b of the curve.

The NSA provided those seeds with no explanation or justification, and the post reproduces the P-256 seed, C49D3608 86E70493 6A6678E1 139D26B7 819F7E90, as an example of a value published with no information about where it came from. Neal Koblitz and Alfred Menezes summarized the controversy in the paper “A Riddle Wrapped in an Enigma,” and the question later drew an amateur investigation into the seeds’ origins…